I was given to believe that there was only one solution to each sudoku problem. In this mornings Wash Post (12/19/07) I found that there were two solutions, involving three 6/9 cells which could be resolved in two different ways.

Then when I entered the key five digits for that puzzle( 23629) to Sudoku.com, I was given a third solution to the puzzle--quite different except for the 5 digit (23629) generating key and the remaining digits of the key (54138527681864571278374). What gives? Ren't solutions unique? [Obviously I am new at this game.]

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